Magnetic Resonance Imaging (MRI) is becoming a critical tool in real-time molecular imaging research. It is particularly beneficial as a non-invasive method for 3D, high resolution, spatial imaging of deep tissue in living samples. With the advent of MR spectrometers of ultra-high field strengths like the 9.4T microimager, it is possible to study biological structures in vivo with a resolution of 50 micrometers or less. When ultra-high field imaging is combined with the use of contrast agents, it is possible to image biological processes. Such techniques, if applied to cancerous tumors, may contribute to the diagnosis and treatment of these disorders. Prostate cancer is the second leading cause of death from cancer and is most common malignancy in North American men. One of the factors present in malignant prostate cells and shown to support its metastatic growth is the neuropeptide neurotensin (NT). Recently, scientists at University of Massachusetts Medical School (UMMS) have developed a contrast agent for visualizing NT receptors. Using an in vitro model it has been shown that this ligand can be followed as it concentrates in cells via receptor mediated endocytosis. The primary goal of this initiative is to establish the feasibility of using ultra-high field imaging techniques with paramagnetic ligands (as contrast agents) as a method for following prostate tumor growth and progression in an in vivo model. If we are successful with the first phase (R21), then the second phase of this grant will focus on the effects of androgen ablation and NT levels on tumor motility and growth in the same animal overtime in an attempt to understand better the use of non-invasive techniques for identifying and tracking prostate tumors.